A wheeled tractor scraper (scraper) is a self-propelled construction machine used for transporting material over short distances. The scraper generally consists of a tractor that tows a vertically movable hopper known as a bowl over a ground surface. A horizontal blade is connected to a leading lower edge of the bowl such that, when the tractor tows the bowl forward and the bowl is lowered, the horizontal blade cuts into the ground surface and fills the bowl with excavated material. After the bowl is loaded to capacity, the bowl is raised away from the ground surface and closed at the leading edge by a vertical blade known as an apron. The scraper then transports its load to a dump area where the apron is raised and an ejector located at a back end of the bowl pushes the load forward out of the bowl. The cycle is then repeated until a desired amount of material has been moved.
During operation of the scraper, it can be important to keep track of the number of cycles completed by the scraper. For example, the number of cycles completed by a scraper may be used in determining a depreciation value and/or maintenance schedule for the scraper. In another example, the number of cycles completed by the scraper may aid in calculating a volume of material moved by the scraper, the volume being used for billing and scheduling purposes. In the past, the cycles were manually counted by an operator of the scraper. Unfortunately, this method of tracking cycles was prone to both inadvertent error and intentional manipulation. Accordingly, an automated cycle counter is desired.
An exemplary automated cycle counting system for a scraper is disclosed in U.S. Patent Publication Number 2006/0104404 of Blackburn et al. that published on May 18, 2006 (“the '404 publication”). Specifically, the '404 publication discloses a dump actuator, a manually-operable lever configured to control the dump actuator, a transmission gear sensor, and a cycle counter. The cycle counter is configured to record one dump cycle when the control lever is pushed by an operator into a dump position and held in the dump position for at least five seconds after the transmission gear sensor indicates that a transmission gear of the scraper has exceeded first gear.
While the automated cycle counting system of the '404 publication may help to avoid disadvantages associated with manually counting cycles, the system may still be less than optimal. Specifically there may be situations where the control lever is pushed to and held in the dump position, but no dumping occurs. This situation may present itself when the ejector of the scraper becomes stuck or blocked by a rock and is not moving, even though the ejector is being commanded to move via the control lever. In this situation, the system of the '404 publication may erroneously record a cycle count even though the cycle has not been completed.
The present disclosure is directed to overcoming one or more of the problems set forth above and/or other problems of the prior art.